In the 3GPP (Third Generation Partnership Project) that defines a standard for mobile network systems, EPC (Evolved Packet Core) is specified as the next generation mobile network system. The EPC is a network system that accommodates an LTE (Long Term Evolution) access network in addition to radio access networks called the second generation and the third generation.
The state where a mobile communication device that is located in an LTE wireless area is connected to the EPC is referred to as “ECM-CONNECTED” state. The mobile communication device may be referred to as a mobile terminal device. Further, the mobile communication device is defined as a UE (User Equipment) in the 3GPP. Furthermore, a device that manages the location of the UE that is located in the LTE wireless area is MME (Mobility Management Entity), and a device that manages the location of the UE that is located in the second and third generation wireless area (which is referred to as “3G wireless area”) is SGSN (Serving GPRS Support Node).
It is anticipated that, initially after introduction of the LTE wireless area, the LTE wireless area will be gradually broadened, overlaying the 3G wireless area. In the case where the LTE wireless area and the 3G wireless area overlap and the LTE wireless area is small, switching between the LTE wireless area and the 3G wireless area is anticipated to occur frequently in the UE that is located at the end of the LTE wireless area. The frequent switching between the LTE wireless area and the 3G wireless area causes problems such as an increase in network processing load due to location registration processing and battery consumption of the UE.
In Non Patent Literature 1, the LTE/3G location registration skip feature (ISR (Idle mode Signaling Reduction) feature; hereinafter referred to as the ISR feature) that does not carry out location registration even when a UE moves to a different area unless there is no change in the location registration area that has been registered before in the LTE wireless area and the 3G wireless area. Enabling the ISR reduces the number of times location registration is carried out, and it is thereby possible to solve the problems of an increase in network processing load and UE battery consumption.